Why is it surprising? He used equivalent settings and got almost equivalent results. The 5d3 is only about 1/2 stop more efficient than the 40D.

It's still surprising. The 5D3 sensor, as you note, is more efficient, and by virtue of the greater pixel count, NR (noise reduction) should make the balance of noise/detail fall further into its favor.

At this extreme ISO, the extra resolution coming from the more pixels and the less enlargement is mostly gone. For a closeup like this, the lower DOF would decrease the apparent sharpness.

But this is not so interesting, IMO. Most of the people here are under the impression that the crop body somehow performed equal to the FF, expecting about 2 stop difference and seeing almost none; without realizing that the expected advantage should be just 1/2 stop. I do not think that anybody would be surprised, if after heavy NR, the 5D2 and the 5D3 would look quite similar.